Workpiece loading fixture



Nov. 12, 1968 c. J. ALBRECHT WORKPIECE LOADING FIXTURE Filed March 28, 1967 T H C E RR m8 L N A |l V w III L II R H A I] c ii l BY w ATTORNEYS I United States Patent 3,410,594 WORKPIECE LOADING FIXTURE Carl J. Albrecht, Kronberg, Taunus, Germany, assiguor to Kolene Corporation, Detroit, Mich. Filed Mar. 28, 1967, Ser. No. 626,628 1 Claim. (Cl. 29481) ABSTRACT OF THE DISCLOSURE A power cylinder-operated lazy tong linkage supports aplurality of evenly spaced workpiece carrying hooks, and is selectively operable to uniformly increase or decrease the horizontal spacing between such hooks as required by the characteristics of the particular heat treating bath into which the load of workpieces is to be immersed.

BACKGROUND OF THE INVENTION Each of the various heat treating immersion processes has unique characteristics which dictate certain optimum spacing between submerged workpieces. Where a sequence of immersion steps is involved in a particular operation, it becomes desirable to vary the spacing between the workpieces as the workpieces move from one step to the next.

An example of this situation is where molten salt baths, such as are used in carburizing, and quenching tanks are used as adjacent operations. For reasons of economy, it is desirable that molten salt baths be as compact as possible, and to treat as many pieces as the bath will accommodate, thus dictating an extremely small spacing between parts. Even point or line contact between parts is not detrimental to a carburizing process. However, in a quenching operation, the formation of steam from the quench water or the reaction with nitrate-containing salt mixtures produces uneven cooling effects if the heated workpieces are packed too closely together. In a martempering operation, there is the further risk that the workpieces will be thrown about if too closely packed.

This invention overcomes the above problem by providing a means for quickly and easily adjusting the workpiece spacing as the workpiece supporting device travels between immersion tanks.

This and other objects and advantages of this invention will become more apparent from reference to the following specification when read in conjunction with the accompanying drawings.

In these drawings:

FIG. 1 is an elevation partly in section showing the device of this invention, and wherein the workpiece supporting device is shown in two conditions.

FIG. 2 is a fragmented section of the linkage viewed in direction of arrows 2-2 of FIG. 1.

DETAILED DESCRIPTION The drawings illustrate a supporting device from which are suspended a plurality of workpieces 12 immersed in a treating tank 14. Workpieces 12 hang from hooks 16 which are in turn uniformly spaced along and connected to lazy tong linkage 18. As is best illustrated in FIG. 2, hooks 16 are suspended from axles 20, each axle carrying a pair of rollers 22 which ride on angleshaped tracks 24 forming a portion of frame 26.

The right hand end of linkage 18 is fixed to a stationary bracket 28, while the movable left hand end of the link- 3,4l,594 Patented Nov. 12, 1968 age is connected to piston rod 30 of actuating cylinder 32. Reciprocation of piston 34 within cylinder 32 is effected by selectively operable valve 36 which controls the application of hydraulic or pneumatic pressure to the respective ends of the cylinder. Linkage adjustment could also be controlled by mechanical means. Supporting device 10 may be conveyed to adjacent immersion tank 38 by means of a pair of traveling hoists 40 which ride along beam 42 and which permit the load of workpieces to be raised and lowered.

In operation, tank 14 may be considered by way of example as a molten salt bath, wherein it is desirable to provide extremely close spacing between adjacent workpieces to minimize the quantity of molten salt material required. This minimum spacing is accomplished by setting valve 36 to drive piston 34 toward the right hand end of cylinder 32 to compress linkage 18. When the immersion operation is completed, supporting device 10 would be elevated by traveling hoists 40 and displayed horizontally until it was in position over tank 38. Assuming that tank 38 were a quenching or martempering tank, valve 36 would be actuated during movement between tanks to advance piston 34 toward the left end of the cylinder, thereby providing the desired increased spacing between the workpieces appropriate for quenching. Thus when workpieces 12 reach position over tank 38, the desired spacing would already be established and they would be ready to be lowered into the tank.

It can thus be seen that the loading fixture of this invention provides a rapid and reliable means for setting workpiece spacing as required by heat treating operation characteristics.

I claim:

1. Apparatus for supporting and transporting workpieces during and between multiple heat treating immersion operations comprising:

a travelling hoist;

an enclosing frame suspended therefrom;

means on said hoist for raising, lowering, and transporting said frame;

a power actuator inside of and enclosed by said frame;

a horizontally extensible and retractible lazy tong linkage inside of and enclosed by said frame, and having axles at the lower ends of the links; said axles being within and riding on the lower horizontal part of said frame;

said linkage having one end fixed to said frame and its other end fixed to a horizontally movable part of said actuator, whereby the linkage may be extended or retracted;

and suspension hooks carried by the axles of said linkage and extending vertically below said frame.

References Cited UNITED STATES PATENTS 1,723,086 8/1929 Smith 2948l 3,302,967 2/1967 Harris 29465 FOREIGN PATENTS 922,791 4/ 1963 Great Britain.

EVON C. BLUNK, Primary Examiner.

H. C. HORNSBY, Assistant Examiner. 

